We try out the best photo editors on Linux

Multithreading & performance

Fancy features are all well and good, but can it get the job done fast?

Camera sensors are getting bigger, more of us like to work in RAW formats and bandwidth limitations are no longer critical for reducing picture quality and size before uploading. Plus, we're shooting a lot more photos than ever before. Image files aren't getting any smaller, and our libraries are expanding rapidly. So photo editors are in a Red Queen race: they need to be more efficient than ever just to seem as good as they were.

With the exception of Fotoxx, all of our software here is multi-threaded and can take advantage of more than one processor core. digiKam and Shotwell are surprisingly fast at dealing with large libraries of photos and helping you find the shot you want. Neither are perfect, though: Shotwell feels a little buggy and slows down at seemingly random periods, while digiKam's interface is often the stumbling block. Opening up a RAW file, for example, means going through a tedious and old-fashioned import screen rather than going straight to the meat of the editing tools.

As far as our dedicated RAW editors are concerned, AfterShot Pro is incredibly fast at cataloguing and editing files, and designed to get the most out of your workflow. It's still a little sluggish at dealing with picture layers, though, so you'll likely want to fall back on Gimp for fine grain editing.

Darktable, meanwhile, is fleet-footed in thumbnail mode, but once you start layering edits onto an image it quickly takes its foot off the metaphorical gas and begins to get frustratingly slow. Even zooming in to a shot takes too long (and there's no slider to show you how far you've zoomed in either).

The triumph of the latest release of Gimp, meanwhile, is its support for multi-threaded processors and - if you're prepared to tinker - OpenCL for GPU acceleration, too. The upshot is that nothing on Gimp 2.8 feels like a chore, so long as you know what you're doing.

The verdict

One thing we haven't covered is picture quality. Gimp remains the only really serious tool for all-round work; Darktable gives AfterShot a run for its money, but struggles without a hefty CPU behind it.

Ultimately, there is no one tool that does it all, and where applications try to take photos all the way from hard drive to output in one go they inevitably fall down somewhere.

AfterShot Pro's library management is a bit too intense for daily use if you're just browsing through old snapshots, while digiKam's RAW developer would drive you insane. The best set-up for RAW shooters would be Shotwell for image management and AfterShot Pro or Darktable for developing pictures.

For the casual snapper, digiKam works wonderfully on both KDE and Gnome, although you'll probably end up wanting to cover two thirds of its icons with sticky tape. Where Shotwell's editing tools are too basic for most, digiKam can be quite overwhelming.

Which brings us onto Gimp. That it should, after all these years, remain the only real choice for lightweight or heavy lift editing activities seems like a missed opportunity, but the only piece of software that can survive without its touch-up skills is AfterShot Pro - and even there it's easier to fall back on Gimp for fine tuning.

It's not often in Linux that there's only one way of doing things, but we feel everyone who edits photos should have Gimp installed. The lack of 16-bit colour precision means it has limitations for professionals, but it's more than adequate for most needs.

So what of AfterShot Pro? It pains us to admit it, but the fact that this is the product of a large company with a lot of resources shows. Only Gimp comes close to its level of sensible design choices and bug-free execution, and even then it tends to stray off into a slightly bonkers world of its own. We salute Corel for continuing to support Linux with such a fine piece of software.

Fotoxx is wonderfully quirky, and has an insane feature set for an application that appears so simplistic on first boot, but it's not mature enough yet to compete with the established names.